1. Field of the Invention
This invention relates to a magnetic head, and more particularly pertains to a mutli-track magnetic head.
2. Description of the Prior Art
In order to store information on a medium by means of magnetic recording techniques, the recording current supplied to the magnetic head windings is required to magnetize the medium. Whether the method of bias recording or non-bias recording is used, in the case of a multi-track magnetic head having a large number of unit magnetic heads, the electrical power required to energize those heads simultaneously will be quite large.
FIG. 1 shows a multi-track magnetic head 1 in which a large number of unit magnetic heads 2 are assembled, and packed in a casing. In order to record the signal on the magnetic recording medium 3 by letting the recording current simultaneously flow in all the unit recording heads with track numbers from T.sub.1 to T.sub.n, when the corresponding recording amplifiers 5 numbered A.sub.1 to A.sub.n are electrically connected to the unit magnetic heads 2 numbered T.sub.1 to T.sub.n, and a part or all of the recording amplifiers 5 are put together as an assembly 4, the power consumption by the recording amplifiers is large, if the number of the unit magnetic heads is large, and consequently, the problem of radiation and the problem of heat resistance to heat of the semiconductors themselves which compose the amplifier 5 occurs. In reference to the signal source of FIG. 1, the signal from the input terminal 7 is divided by the divider 6, and is, then, fed to the respective recording amplifiers 5. The input signal source is not limited to this arrangement, and the input signals may be fed from a series of sources.
When the no-bias recording method is used, a rather large electric power capacity is required for individual recording amplifiers 5 shown in FIG. 1; accordingly, the amount electric power required as a whole is very large. Generally, recording amplifiers, covering wide frequency bands are necessary for this arrangement. The use of a large number of high output recording amplifiers is uneconomical. On the other hand, when the bias recording method is used, if bias supplying amplifiers for mono frequency are available, only signal recording amplifiers having small capacities are needed, and accordingly, the power consumption of the assembly 4 of the recording amplifiers can be reduced.
The basic composition of a conventional bias recording system is as shown in FIG. 2. To the winding 9 wound on the magnetic head core 8, the bias frequency f B is fed from the bias amplifier 12 through the high-pass filter or the band pass filter 10, and the signal f S from the recording amplifier 13 is fed through the low-pass filter 11. In order to simultaneously drive a large number of unit magnetic heads of such a construction, they are parallel-connected to the bias power supply, so that the bias may be supplied from a single terminal 14 through the filters 10. As described above, for each unit magnetic head, two filters mainly composed of inductive windings and condensers are necessary. In the multi-track magnetic head in which the number of the unit magnetic heads used is large, the number of these filters and the mutual interactions between these filters pose problems. Furthermore, when these magnetic heads and recording amplifiers are to be formed in integrated circuits by the techniques of vapor deposition or photoetching, the capacitors, etc., of the filters cause difficulties in making such unit heads.